A perfectly harmless companion cube. Absolultely nothing to be afraid of at all. It definitely cannot speak. In fact, if it could speak, I'm sure it would be quite friendly. But that doesn't matter because it can't speak. Or move. And it certainly won't stab you, either. That's for sure.

EDIT: The first time I played with this, it scared me shitless. For some reason I really didn't want to disconnect, I just wanted to see what would happen, and it took me ages to realize it was doing something. Seriously fucking scary stuff for the first time.

I have to congratulate you, this is the first thing in gmod which has actually scared me. As in Really scared me. Almost as much as watching the ring. Keep working on it, it needs more stuff. Maybe you turn to face it, and see a face which disappears very quickly. Or see flashes of it in the corner of your eye, then turn around and it's behind you.

That thing actually scared me while i was playing on Dustbowl.
1. I decided to try and keep an eye on it, so i placed a camera and turned away. It didn't move. I placed an RT camera and placed a monitor. I think it moved in front of me.
2. I place a PHX window (a couple actually). It moved through them. Try playing with this thing in Ravenholm :D